Taken from our Jan. Newsletter
FOR THE LOVE OF PLANTS
Article Review
Written by Blazing Star Herbal School Apprentice
Meaghan Weeden
@wildflowersgrowwhereyouare
In the latest issue of Herbal Gram, the American Botanical Council followed up on the question posed by their 2009 article, “Climate Change Impacting Medicinal Plants?”—to which the answer is a resounding YES. In that article, they conducted an extensive review, aided by scientists on the ground, of the measurable effects that Climate Change was having on medicinal and aromatic plants (MAPs). 10 years later, they’re back, having followed up with most of the scientists quoted in the original article. Focusing on traditional food and medicine plants in arctic, alpine, rainforest, and island ecosystems around the world, their findings are both unfortunate and unsurprising. From rapidly warming Himalayan mountaintops to dissipating cloud forests in central Mexico, biodiversity hotspots around the globe are under serious threat.
In the alpine regions of North America, Europe, and Asia, mountain surface area temperatures are increasing at a faster rate than the global average. This combined with precipitation changes is directly impacting endemic alpine flora. As these regions warm, tree lines and lowland species advance upward, putting competition pressure onto the slow-growing native species that have adapted over thousands of years to conditions that no longer exist. As one scientist put it, they’re running out of mountain. Specifically, in the Himalayas, cordyceps fungus, which is already impacted by over harvesting and ecosystem degradation, faces amplified pressure thanks to climate change. The mountaintop landscape of this region is rapidly changing and diversifying as climatic conditions change and lowland species flee the warming temperatures of their native altitudes. These heat-loving, drought tolerant plants crowd out their more sensitive cousins, fueling the rise of local extinctions.
On the desolate arctic seashores of Alaska and Canada, Rhodiola is threatened by warming temperatures and eroding shorelines. In the interior, wild berries, a vital survival food for the Inuit, adapt to rising temperatures by growing taller and shifting their chemistry, affecting accessibility and nutritive benefits. In the Pacific Islands, threats include rising sea levels, extreme weather, foreign logging and fishing, changing ecology of mangrove swamps and coastal stand zones and, interestingly, international aid that favors foreign foods and medicines over local and indigenous ones. Some endemic species may, thanks to this ecosystem degradation, be lost to history.
In Central and South America, scientists are attempting to measure the affects of cloud dissipation on the Tropical Montane Cloud Forests and paramo across Mexico, Central America, the Caribbean, Northern South America, and parts of southeast Brazil. These unique ecosystems are home to thousands of unique species and, in Central Mexico, provide vital overwintering habitat for millions of Monarch butterflies. Their findings are showing that the vegetation, adapted to mist and fog, will be significantly impacted by these changes—specifically, “threatening the growth and survival of both mature trees and a range of eniphytic plant groups.” A 30 year study in Amazonia shows that the composition of the forest is evolving in response to warming and drought, but that these changes aren’t keeping up with Climate Change. In the Andes, species are migrating up the mountains to cooler elevations, but again, not fast enough to avoid species loss.
Plants are no strangers to harsh conditions necessitating adaptation, and every species we know today has survived the inevitable ecosystem shifts of a fluid planet by evolving with it. What we’re seeing now, however, are major climatic changes happening in real time and at breathtaking speed. This unprecedented speed is what threatens the existence of all species, including humanity. With every new offshore drilling project, climate change denial, or uncontrollable wildfire, we hurtle towards a barren, desolate future that will test our collective will to survive.
Even with the odds against them, plants and ecosystems are valiantly adapting and adjusting to the harsh new realities they face. However, what is encouraging for plants may be less so for us. Many of the medicinal compounds (active plant secondary metabolites) that we rely on for nutrition and herbal medicine are produced in response to specific environmental stressors and may decrease or disappear altogether as the climate changes. For example, the wild berries that the Inuit depend on have been found to produce higher levels of antioxidants in the coldest regions of the arctic, which are rapidly warming. Thus, scientists are concerned that our treasured medicinal and traditional food plants will lose their potency at a time that they are most needed.
To address these threats, scientists are developing ways to determine which plants will need the most help and how to manage them. To this end, they've determined what characteristics are best suited for the coming climatic changes, both experienced and expected. Plants that are more tolerant of drought have higher wood density, thicker leaves, higher water use efficiency, and deeper roots. Plants that are tolerant of higher temperatures have thicker leaves, greater below-ground biomass, and adaptive height. Plants that can tolerate frequent wildfires have thicker bark, serotinous cones, and the ability to resprout after fires have torn through. Plants with a combination of these traits will likely cope best, while plants without them could easily fall behind—and should be the focus of conservation efforts.
In the face of Climate Change, human ingenuity and intervention are going to be needed more than ever to keep MAPs growing and thriving. In Oregon, one scientist is experimenting with several orchard management techniques to develop ways to continue growing apples in less than ideal conditions. So far, he has found the most success with a simplified version of Huerta, the integrated orchard-garden systems of Spain and Italy. Another industry that they expect will be greatly affected is wine. Already, vintners wise to the reality of Climate Change are looking for new areas to move their orchards to once the traditional wine regions become unsuitable.
Patterns have emerged regarding the relationship between plant phenology (seasonal activities) and the climate. In general, the phenology of many plants has already changed, especially in temperate zones. One contributing factor is the rise of earlier, warmer springs, and of false springs (when the temperature warms up enough to cue the production of buds and leaves in temperature reliant plants, but the last frost has yet to occur). For many frost-sensitive plants, these false springs can prove disastrous. For other plant species that become active later in the season, these timing shifts can cause serious phenological mismatches—from flowers that bloom before the pollinators are out to fruits that appear after birds and other dispersers have migrated.
The challenges presented by an increasingly unpredictable climate are clear and give the upper hand to invasive species that are more phenologically labile (fluid). Plants that can better adapt to temperature changes increase their performance accordingly, while those that can’t will decline and die out. The most vulnerable species are the ones that not only fall victim to false springs and phenological mismatch, but are also less mobile and cannot migrate quickly enough to more favorable habitats.
“In the face of a changing world, plants have choices: die out, move, or adapt.” Those species with the ability to migrate are increasingly being found outside of their ranges, which will eventually lead to the decline of their native ecosystems. Surveys of European mountain summits dating back to 1871 have shown some troubling trends, including an increase in species gain over the last 145 years, with a significant acceleration over the last 20-30 years. Scientists observe that this acceleration is “strikingly synchronized with accelerated global warming”. This frenzied growth may seem like a good thing, but, in reality it is not a good sign. In the future, the ability to track and forecast phenology and range will play an large role in the conservation of both wild and cultivated plants. The plants have always helped us, but they cant save us from ourselves.
All of this information can feel incredibly overwhelming, but with great struggles come great opportunities. The climate crisis is our collective wake-up call, and forces us to take stock of the ways we are living. Is this the direction we want to go in? Is this the end, or just the beginning of a new age? While we can’t truly know what the world will look like in 50 or 100 years, we can work towards the brighter future that our children deserve. In the words of the Independent Alliance of World Scientists, “We declare, with more than 11,000 scientist signatures from around the world, clearly and unequivocally, that planet Earth is facing a climate emergency. The climate crisis has arrived and is accelerating faster than scientists expected. It is more severe than anticipated, threatening natural ecosystems and the fate of humanity. To secure a sustainable future, we must change how we live. The good news is that such transformative change, with social and economic justice for all, promises far greater human well-being than does business as usual.”
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